1. Field of Disclosure
This disclosure generally relates to an alignment device for aligning a structural member, such as a bushing, as the structural member is being radially expanded and installed into a workpiece.
2. Description of the Related Art
Structural members, such as conventional bushings with radial flanges, are commonly installed into openings of workpieces for a variety of reasons. For example, the body of the bushing typically reinforces or structurally supports the region around the opening. In addition, the radial flange of the bushing may operate as a washer to transmit the fastener clamp-up loads into the workpiece and/or structural joint, define a bearing surface for bolts, define a wear surface, and the like.
One method for installing bushings, especially in components that will undergo repetitive load cycles and/or may be susceptible to accumulating fatigue damage, is the FORCEMATE® installation method developed by Fatigue Technology, Inc. The FORCEMATE® installation method utilizes an expansion mandrel received in an installation tool. The mandrel is passed through a passage in the bushing after the bushing has been placed in the opening of the workpiece. The mandrel radially expands the bushing into the opening to obtain a controlled, but consistently higher, interference fit than would be achievable by other installations methods, such as shrink or press fitting methods. In addition, the FORCEMATE® installation method may induce beneficial residual compressive stresses into the structural material surrounding the opening, which may advantageously extend the fatigue and damage tolerance (i.e., crack growth) life of the component, assembly, and/or installation. The FORCEMATE® installation method, as well as other cold-working methods, tooling, and the like, such as the BUSHLOC®, FORCETEC®, and FLEXMATE® methods are described in U.S. Pat. Nos. 3,566,662; 3,892,121; 4,187,708; 4,423,619; 4,425,780; 4,471,643; 4,524,600; 4,557,033; 4,809,420; 4,885,829; 4,934,170; 5,083,363; 5,096,349; 5,405,228; 5,245,743; 5,103,548; 5,127,254; 5,305,627; 5,341,559; 5,380,136; 5,433,100; and in U.S. patent application Ser. Nos. 09/603,857; 10/726,809 (U.S. Pat. No. 7,100,264); Ser. No. 10/619,226 (U.S. Pat. No. 7,024,908); and Ser. No. 10/633,294 (US/2005/0025601). Other techniques for radially expanding the structural member into the workpiece may use a hydraulic or a pneumatic actuated installation tool that is capable of moving the expansion mandrel through the structural member with a large amount of force.
One drawback with at least some of the aforementioned installation techniques and/or tools is that the weight of the installation tool may influence the alignment of the expansion mandrel relative to the structural member and/or the opening in the workpiece. In addition, the mandrel pulling force generated by the tool to pull the mandrel through the structural member has nothing to react against the pulling force until an expansion portion of the mandrel contacts and actually begins to expand the structural member. If such initial contact occurs when the structural member is misaligned in the opening of the workpiece, then the large pulling force, which may be 20,000 pounds or greater, tends to radially expand the structural member into the workpiece in the misaligned orientation.
As a result, gaps may occur between the radial flange of the structural member and the corresponding surface of the workpiece. The gaps may adversely affect the ability of the radial flange of the bushing to transmit the fastener clamp-up loads into the workpiece. Further, the gaps may result in the structural member failing to meet specific flushness requirements. Thus, the gaps may require that a post-installation seating process be performed on the structural member to properly seat the radial flange against the workpiece. If the gaps are too big, the installed structural member may have to be removed from the opening and replaced with another structural member, which may require re-drilling and oversizing the opening in the workpiece. Additionally or alternatively, residual stresses that may be intended to be induced into the workpiece during the radial expansion of the structural member may be non-uniform, or even non-existent, in some regions across the thickness of the workpiece.
Based on the foregoing, it would be desirable to have an alignment device that can be used with an installation tool to more predictably install the structural member while overcoming at least some of the aforementioned drawbacks.